Birmingham Roller Squab Colors

Hello, I have had my first hatch of squabs yesterday under my pair of birmingham rollers. Mom is almost solid red, and dad is red/blue pied. So the question is, how early can you tell the color on the babies? Right now they are both yellow obviously.

They will molt possibley to totally different colors at six months n even moult after that maybe, than what feathers look from under six months. I've got a black pair that throw mostly reds. go figure.